Rest Frequencies for Alkaline Earth Hydroxide Radicals (X 2 Sigma +)

High-resolution laser excitation spectroscopy of the transition of BaOH

“…The R 22 /Q 21 paired lines start to be resolved at around J 00 = 14.5/15.5, respectively. The rotational (J) assignments of all the observed bands were made using lower state combination differences in the e X 2 R þ state [9]. 878 lines in the 12 branches of the e…”

“…The measured lines of the e A 2 Pð0 0 0Þ À e X 2 R þ ð0 0 0Þ transition were modelled using a standard Hund's case (a) 2 P À 2 R + Hamiltonian [18]. A combined least-squares fit was performed, which included the 878 lines of the e A 2 Pð0 0 0Þ À e X 2 R þ ð0 0 0Þ transition (this work) and 47 pure rotational lines of the e X 2 R þ ð0 0 0Þ state [9].…”

“…In this group of molecules, CaOH [2][3][4][5] and SrOH [6][7][8] have been extensively studied using laser spectroscopy. Pure rotational analysis of several vibrational bands in the ground state of MgOH, CaOH and BaOH has been completed using millimeter-wave absorption spectroscopy by Ziurys et al [9]. Transition frequencies and precise molecular constants have been derived from this analysis, which largely facilitate rotational analysis of excited electronic states.…”

Optical–optical double resonance spectroscopy of the transition of CaOH

“…b Combined fit of theD 2 R þ -à 2 P transition data,X 2 R þ state millimeterwave data [18], and theà 2 P-X 2 R þ transition data [10,11]. Table 2 Bond lengths (Å ) for CaOH [18] and CaOD [20]. b Determined from the optical data of CaOH [10,11] and CaOD [24].…”

“…Thẽ C 2 D-X 2 R þ transitions of both CaOH and CaOD have been recorded at high resolution using the technique of laser excitation spectroscopy [15,16]. Pure rotational transitions in the ground state have been recorded by millimeter-wave spectroscopy [17][18][19][20] and hyperfine constants arising from the hydrogen nucleus have been determined in theX 2 R þ state using the pump/probe microwave-optical double resonance technique [21]. Finally, the dipole moment of CaOH in theX 2 R þ ,Ã 2 P, andB 2 R þ states has been determined using Stark spectroscopy [22].…”